Metallic tube press



Oct. 2, 1934. F: HANFF I 1,975,455

METALLIC TUBE PRESS Filed Dec. 5, 1932 ii 4% I jflT 7 I g. I

Patented Oct. 2, 1934 METALLIC TUBE mass Ferdinand Hanff. Berlin-Charlottenburg, Germany, assignor to Siemens-Schuckertwerke Aktiengesellschaft, Berlin-Siemensstadt, Germany, a corporation of Germany Application December 5, 1932, Serial No. 645,738 In Germany December 7, 1931 3 Claims. (Cl. 2074) My invention relates to presses for the manufacture of metallic tubes, and more particular-'- ly to leadcable presses.

In the presses for the manufacture of lead 8 cables, in which the cable runs transversely to the axis of the press cylinder, difliculties have hitherto been encountered in avoiding the formation of so-called welded seams. These welded seams impair the strength of the lead sheaths,

l particularly in the case of oil-filled cables, and may give rise to serious troubles. 1

The object of my invention is to overcometo a considerable extent the drawbacks present in the heretofore known presses. To this end, the

[ extrusion chamber is so designed as to cause in the latter a reversal of flow of lead. As compared with the prior art presses, the flow of lead in the device according to the invention does not, consequently, take place by passing over the mandrel holder in a direction parallel to the die,

but in such a manner that the-lead after entering the extrusion chamber, at first flows around the die holder and then impinges upon the mandrel holder and then by reversing its direction,

flows into the die. To cause the lead to follow the path, the die holder may, for instance, be so designed as to project into the extrusion chamber and preferably to extend laterally be-' yond the imaginary extension of the press cylinder. The mandrel holder may be to advantage arranged in such a manner that a part of it by projecting into the extrusion chamber causes a total or partial reversal of the flow direction of the lead.

My invention is illustrated in the accompanying drawing, in which- Fig. 1 shows a central sectional elevation of the extrusion chamber of a cable press, and

Fig. 2 shows in similar view a modification by 40 the arrangement of flow restricting ridges.

In Fig. 1, 1 denotes the lower portion of the press cylinder to which is connected the extrusion block 2 which contains the extrusion champer 3. In this block are mounted in axial alinement, but transverse to the press cylinder axis, the die holder 4 carrying at its inner end the die 6, and the mandrel holder 10 carrying at its inner 'end the extrusion mandrel 9. The latter guides the cable to be sheathed into the sheathing die 6 0 from which the sheathed cable 8 emanates. In

order to avoid or correct inaccuracies in alinement between the extrusion die and the sheathing die, the former is spherically shaped at its base 13 and rests with this portion in a correspondingly shaped split socket 14.

It will be noted that the point in the extrusion chamber at which the two aforementioned dies cooperate is shifted a considerable distance laterally of the press cylinder axis and is located in a lateral extension of the extrusion chamber 3. In designing this chamber in this manner the great advantage is obtained oflengthening the pathway of the lead without lengthening the extrusion chamber vertically. The lead expelled from the lower end of the press cylinder enters the extrusion chamber and moves first around and along the sheathing die toward the extrusion mandrel until it strikes the pocket 5 at the extreme end of the extrusion chamber, where the flow is reversed and directed toward the sheathing die 6. By these means the metal is well mixed and. kneaded. However, in order to knead the metal on its way to be extruded more thoroughly than is possible by the aforedescribed mere reversal of flow, and to render the mass still more homogeneous, it is preferable to additionally restrict the pathway of flow in a manner wellknown in the art. vIn the present case such a restriction may be provided most conveniently on the extrusion chamber wall in the form of an annular ridge 11. If desired, such a ridge may advantageously also be provided near the inner end of the die holder 4 for instance as shown at 12 in Fig. 2.

In order to protect the cable '7 against excessive pressures, it is of advantage to mount the cable extrusion die 9 with respect to die 6 so that it extends a short distance into the funnelshaped mouth of die 6.

By extending the pathway for the lead and by reversing its flow, an equalization of the differences in pressure and of the velocities of flow is attained, as well as an equalization of the temperatures of the metal to be extruded, which is of great importance as to the properties of the finished tube. Since a shifting of the lead crystals occurs at the point of reversal in the pathway in which the lead flows-50 to say, a kneading of the total metal to be extruded takes placethe oxide films, present in the lead are triturated tosuch an extent as to result in harmless particles, which will not cause the appearance of the so-called welded seams with the accompanying danger of leakages, so that a faultless homogeneous tube is obtained. A further advantage of the device. according to the invention consists in the fact that owing to the reversal of flow of lead, special pressure equalizing rings in front of the inlet opening which are otherwise necessary in the usual presses may be, dispensed with. In this manner an extrusion device realong the end of said tube die holder a distance beyond the extrusion point of said dies in a direction opposite to that in which the material is to be extruded and means closely adjacent to said dies for guiding the material back toward the extrusion point in the direction of extrusion;

2. In a tube extrusion press a die block having an extrusion chamber, said chamber having a pocket in one of its wall portions, a tube die holder having a tube die at its end and extending transversely through said chamber and into said pocket and forming adjacent to its end an annular passage with the entrance walls of said pocket in which passage the extrusion material flows along said holder into the bottom of said pocket in a direction opposite to that in which the material is to be extruded, a core die in said pocket operatively alined with said tube die and protruding from the pocket bottom to the extrusion point in said tube die, whereby the extrusion material is guided back from the pocket bottom to the extrusion point in the direction of extrusion.

3. In a tube extrusion press a die block having an extrusion chamber, said chamber having a pocket in one of its wall portions, a tube die holder having a tube die at its end and extending transversely through said chamber and into said pocket and forming adjacent to its end an annular passage with the entrance walls of said pocket in which passage the extrusion material flows along said holder into the bottom of said pocket in a direction opposite to that in which the material is to be extruded, a core die-holder in said pocket and a core die in said holder, operatively alined with said tube die, said core holder and die protruding from the pocket bottom to the extrusion point in said tube die, whereby the extrusion material is guided back from the pocket bottom to the extrusion point in the direction of extrusion, said core die being ball-and-socket jointed in its holder, to render it axially alinable with said tube die.

FERDINAND HANFF. 

